Gastroparesis is characterized by delayed gastric emptying in association with nausea, vomiting, fullness, early satiety, and pain that has devastating impacts on quality of life. Over 5 years, the Gastroparesis Clinical Research Consortium (GpCRC) has improved understanding of this disorder and advanced goals of patients, physicians, and the NIH for its care. Much still needs to be learned about its etiology, course, and therapy that serve as rationales to continue the consortium. This application has 3 specific aims. The first aim is to complete approved studies of the GpCRC including NORIG, a trial of nortriptyline vs. placebo for idiopathic gastroparesis (48 of 140 patients recruited to date), GLUMIT-DG, a study of the safety, feasibility, and potential efficacy of continuous glucose monitoring and insulin pump therapy in diabetic gastroparesis (2 of 40 recruited to date with 2 screened at Univ. of Michigan, APRON, a trial of aprepitant vs. placebo for nausea of presumed gastric origin (initiating 9/2010), and PBG, the pathological basis of gastroparesis (125 biopsies of 200 planned). The second aim is to maintain, expand, and refine the Gastroparesis Registry that enrolled 587 patients from 2/2007-3/2010. We will follow all patients for 4 years and some for 9 years. Informed by insight from the Registry, we propose recruiting more patients to answer new questions relating to pathogenesis, severity, complications, therapies, and outcomes of gastroparesis. The third aim will employ a novel wireless motility capsule (WMC) to characterize the role of generalized dysmotility in producing symptoms in patients with presumed gastroparesis. This study will define abnormal gastric, small intestinal and colonic transit and contractility and relate different motor defects to distinct symptom profiles of gastroparesis to give pathogenic insight relating to factors other than gastric emptying that cause different disease manifestations. The second part of the third aim will include a placebo-controlled trial of an osmotic laxative in patients with delayed gastric emptying and colon transit to test if treating distant dysmotilities improve a range of symptoms of gastroparesis. The studies of this application will significantly advance the knowledge base of the pathogenesis, clinical features, and management of this challenging disorder.